Venetian Blind Positioning Device Cam Disk Mechanism

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Solution Overview

Problem

Existing venetian blind systems require complex constructions to transition from a working position to a closed position without lift tapes, making it difficult to manage the slats' inclination and darkness control.

Innovation Solution

An adjusting device with a cam disk and pick-up lever mechanism, coupled to a drive shaft via a leaf spring, allows for simple activation and deactivation of the working position without elevator belts, using a compact mechanical counter with three cam discs to specify the absolute lowering position of the curtain.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If complex constructions are used to transition from working position to closed position without lift tapes, then the slats' inclination can be controlled, but the device complexity increases

Engineering Contradiction:
Improvecontrol of slats inclinationVSAvoidconstruction complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical constructions with a cam disk mechanism that uses geometric profiles to control the transition between working position and closed position. The cam disk's profiled surface automatically guides the pick-up lever through the necessary movements, eliminating the need for complex linkages or multiple actuators while maintaining precise control over slat inclination.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention changes the control parameter from complex mechanical positioning to simple rotational position of the cam disk. By varying the angular position of the cam disk, the system transitions between different operational states (working position, closed position, and intermediate positions), simplifying the control mechanism while maintaining functionality.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If additional electrical installations are added for controlling blind positions, then precise darkness management is achieved, but the device complexity and cost increase

Engineering Contradiction:
Improvedarkness management precisionVSAvoidelectrical installation complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The cam disk mechanism is self-actuating through the rotational motion of the drive shaft. As the drive shaft rotates to change the blind's position, the cam disk's profiled surface automatically engages the pick-up lever, which in turn controls the intermediate stop and the turning mechanism. This eliminates the need for separate electrical actuators, sensors, or control electronics while maintaining precise control over the slats' inclination and darkness management.

Inventive Principle:
Principle #25Self-service

3Measurement precision

If a compact mechanical counter with three cam discs is used to specify absolute lowering position, then positioning precision is improved, but the device complexity increases

Engineering Contradiction:
Improvelowering position specificationVSAvoidmechanical counter complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The positioning function is segmented into three independent cam disks, each responsible for a specific aspect of position control. The three cam disks work in combination to provide absolute positioning information, with each cam disk's profile contributing to the overall positioning precision. This segmentation allows for modular design and easier manufacturing while achieving high positioning accuracy.

Inventive Principle:
Principle #1Segmentation

4Adaptability or versatility

If the adjusting device is designed for universal application to standard turning mechanisms, then adaptability is improved, but the manufacturing precision requirements increase

Engineering Contradiction:
Improvecompatibility with standard turning mechanismsVSAvoidcam disk profile precision
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The adjusting device is designed with universal features that allow it to be adapted to standard turning mechanisms. The cam disk profiles are designed to work with common drive shaft dimensions and mounting configurations. The housing and mounting structure accommodate variations in standard mechanisms, enabling the same adjusting device to be used across different blind models and manufacturers, thereby improving adaptability while managing manufacturing precision through standardized interfaces.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables easy and independent control of the slats' inclination between open and closed positions, allowing for precise darkness management without additional electrical installations, suitable for standard turning mechanisms and various blind lengths.

Implementation Method 1

coupled to a drive shaft via a leaf spring

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

An adjusting device with a cam disk and pick-up lever mechanism

Methodology Applied
Scientific EffectCam mechanism: Cam

Implementation Method 3

The turning bodies are usually connected to the drive shaft by means of a wrap-spring clutch

Methodology Applied
Scientific EffectSpring force: Spring

Data Source

PatentEP2343431B1Positioning device and method for activating and deactivating the operating position of a Venetian blind
Publication Date: 2020.05.13 GRIESSER HOLDING AG
  • EP2343431B1 patent drawingFigure 1
  • EP2343431B1 patent drawingFigure 2
  • EP2343431B1 patent drawingFigure 3

AI summary

The device has a turning device (1) with a movable control member for predetermining an operating position in a housing. A housing of a positioning device (61) is rigidly connected with the housing of the turning device and a change over device that is coupled with a control member of the turning device. The changing over device comprises a shift lever i.e. tap lever (79), where a position of the shift lever is changed by a drive of a venetian blind in a predetermined lowering position of a curtain. A position of the changing over device is changed independent of lifting elements of the blind. An independent claim is also included for a method for activating and deactivating an operating position with a venetian blind by a positioning device.